Multilayer Clear Over Color Polyolefin Sheets and Layered Backing Structure

ABSTRACT

A multilayer structure includes a clear polyolefin layer, a colored polyolefin layer, and a random polyolefin backing layer. The colored and backing layers are coextruded and are permanently bonded at a layer interface, which is exclusive of an adhesive. The structure has a DOI of 70 or greater and passes a gravelometer impact test per the GM9508P standard, with a 10 pint load, at a −30° C. temperature, and at an impact angle of 30 degrees. Among other uses, the structures are appropriate for use as body panels in the motor vehicle industry. The structures display a “class A” finish and meet a variety of requirements for durability and weatherability. An ABA structured backing layer and a method of making it are also described herein.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of PCT application No.PCT/US09/42704, which was filed on May 4, 2009, which in turn claimedthe benefit of priority from U.S. Provisional Application No.61/050,465, filed on May 5, 2008. These prior applications, includingthe written description and drawing figures, are hereby incorporatedinto the present application by reference.

BACKGROUND

Many different types of articles produced today are formed fromcoextruded or laminated sheets. For the composition of these sheetsthere are several different types of competing technologies, such aspainted plastic, solvent cast fluoro-acrylic film, coextruded ionomerdecorative sheet, painted metal, & coextruded acrylic/ABS sheet.

For many polymeric articles of manufacture, optical and durabilitycharacteristics are very important. Particularly in the transportationindustry, the qualities of distinction of image, gloss, imprintresistance, scratch resistance, mar resistance, and corrosion resistanceare highly desirable among other measures of durability and opticalquality. Achieving a balance of excellent optical qualities andexcellent durability qualities is a difficult endeavor and iscomplicated by the unpredictability of chemical interactions betweenvarious materials used in such compositions. It is particularlydifficult to achieve an excellent balance of properties in a finalformed product that has been subjected to heat and/or elongation.

In addition, sheet formed thermoplastic polyolefin (TPO) typicallyincludes a mixture of both virgin polymer and regrind polymer. TPO is ablend of an olefin, an elastomer, and a filler such as talc. Theaddition of regrind polymer is considered a necessary practice withinthe sheet extrusion industry in order to control costs by minimizingwaste and reducing the overall raw material cost of the final part.Although the economics improve with the addition of regrind, the addedregrind contributes to a lower melt strength and the sag resistance ofthe sheet is significantly reduced. A low sag resistance can causedefects such as excessive “webbing” in tight corners, surface tears inareas of high stretch, and non-uniform wall thickness. Significantvariation in wall thickness throughout a part can cause excessivewarping and/or deterioration of physical properties.

SUMMARY

This application describes novel multilayer structures that include aclear polyolefin layer, a colored polyolefin layer, and a randompolyolefin backing layer. The colored and backing layers are coextrudedand are permanently bonded at a layer interface. In another embodiment,the clear polyolefin layer is also coextruded and permanently bondedover the colored backing layer. These structures have a DOI of 70 orgreater and pass a gravelometer impact test per the GM9508P standard,with a 10 pint load, at a −30° C. temperature, and at an impact angle of30 degrees. The multilayer structures retain DOI and gravelometer impactstandards as stated above even after being subjected to heat and/orelongation to make a final formed product. Among other uses, thestructures are appropriate for use as vehicle body panels.

A formed product is described that includes a coextruded clear isotacticpolypropylene/ethylene copolymer layer of 1 mil to 20 mils in thickness,alternatively 2.5 mils to 20 mils in thickness; a coextruded coloredisotactic polypropylene/ethylene copolymer layer of 3 mils to 20 mils inthickness, alternatively 1 mil to 20 mils in thickness; and a polyolefinbacking layer with a random microstructure. The clear and color layersare coextruded and are permanently bonded at a layer interface. Theformed product has a DOI of 70 or greater. The formed product issubstantially non-oriented by stretching. The formed product has a glossof 75 or greater at a 60° angle and a gloss of 60 or greater at a 20°angle. The clear polyolefin layer has a light transmittance of 90% orgreater. The clear polyolefin layer has a haze of 10 or less. The formedproduct exhibits no gauze imprint at 70° C. minimum under a 500 g loadapplied over a 40 mm diameter for two hours. The formed product passes agravelometer impact test per the GM9508 standard, with a 10 pint load,at a −30° C. temperature, and at an impact angle of 30 degrees.

A vehicle body panel is described herein that includes a multilayerstructure. The multilayer structure includes a coextruded clearisotactic polypropylene/ethylene copolymer layer of 1 mil to 20 mils inthickness, alternatively 2.5 mils to 20 mils in thickness; a coextrudedcolored isotactic polypropylene/ethylene polyolefin layer of 1 mils to20 mils thick, alternatively 3 mils to 20 mils in thickness; and apolyolefin backing layer with a random microstructure. The clear andcolor layers are coextruded and are permanently bonded at a layerinterface. The structure has a DOI of 70 or greater. The structure issubstantially non-oriented by stretching. The structure has a gloss of75 or greater at a 60° angle and a gloss of 60 or greater at a 20°angle. The clear polyolefin layer has a light transmittance of 90% orgreater. The clear polyolefin layer has a haze of 10 or less. Thestructure exhibits no gauze imprint at 70° C. minimum under a 500 g loadapplied over a 40 mm diameter for two hours. The structure passes agravelometer impact test per the GM9508 standard, with a 10 pint load,at a −30° C. temperature, and at an impact angle of 30 degrees.Furthermore, the clear and/or color layers include an additive selectedfrom the group consisting of: antioxidants, UV stabilizers, slip agents,and combinations of these.

In another embodiment, a multilayer structure includes a clearpolyolefin layer, and a colored polyolefin backing layer with a randommicrostructure. The clear and backing layers are coextruded and arepermanently bonded at a layer interface. The interface is exclusive ofan adhesive layer, and the structure has a DOI of 70 or greater. Inaddition, the structure passes a gravelometer impact test per theGM9508P standard, with a 10 pt load, at a −30° C. temperature, and at anangle of 30 degrees.

A method of forming the above structures is also described.

This application further describes a multilayer structure that includesa first thermoplastic layer having a polymeric component consistingessentially of virgin polyolefin, a second thermoplastic layer includingregrind polyolefin, and an optional third thermoplastic layer having apolymeric component consisting essentially of virgin polyolefin. Thesecond thermoplastic layer is adjacent to the first thermoplastic layerand the third thermoplastic layer, if present.

A method for forming a multilayered polymeric structure is alsodescribed. The method includes: coextruding a first thermoplastic layerhaving a polymeric component that consists essentially of a virginpolyolefin with a second thermoplastic layer that includes regrindpolyolefin, and optionally with a third thermoplastic layer having apolymeric component that consists essentially of a virgin polyolefin.The second thermoplastic layer is adjacent to the first thermoplasticlayer and the third thermoplastic layer, if present.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an example coextruded three-layerfilm.

FIG. 2 is a cross-sectional view of an example three-layer film forlamination.

FIG. 3 is a cross-sectional view of an example coextruded four-layerfilm.

FIG. 4 is a cross-sectional view of an example four-layer film forlamination.

FIG. 5 is a cross-sectional view of an example coextruded two-layerfilm.

FIG. 6 is a cross-sectional view of an example vehicle body panel.

FIG. 7 is a cross-sectional view of a second example vehicle body panel.

FIG. 8 is a cross-sectional view of an example multi-layer structurewith an ABA backing layer.

FIG. 9 is a cross-sectional view of an example multi-layer structurewith an AB backing layer.

FIG. 10 is a cross-sectional view of a mono-layer virgin/regrind blendedbacking layer and an ABA backing layer.

FIG. 11 is a graph comparing the “bag time” of a mono-layervirgin/regrind blended backing layer and an ABA backing layer.

DETAILED DESCRIPTION

The example multilayer structures disclosed herein provide a paint-freeplastic sheet structure that may be designed to simulate the appearanceof painted metal or plastic. Example multilayer structures include aclear polyolefin layer over a colored polyolefin layer. Another exampleis a multilayer structure with a clear polyolefin layer over atranslucent polyolefin layer, over a color polyolefin layer. For each ofthese examples the multi-layer structures are provided with athermoplastic polyolefin backing layer. Yet another example includes aclear polyolefin layer over a colored backing layer. Preferably, thereis no adhesive layer at the interface between the clear layer and thecolor layer and there is no adhesive layer at the interface between thelayer attached to the backing layer. Most preferably, the interfacebetween all layers of the multilayer structures is free of alladhesives. An additional disposable mask layer may be provided on eachof the example structures. Furthermore, in some examples, more than onecolor layer, more than one clear layer, and/or more than one backinglayer may be employed.

The example multilayer structures may be formed into an article orlaminated onto a substrate to produce an article. Example articlesinclude a vehicle body panel, bumper fascia, and rocker panel.

In the field of polymeric multilayer sheets, compositional designchanges that result in improvements in one or more optical or materialcharacteristics typically result in a deterioration in another opticalor material characteristic. For example, modifying a product to make itmore durable will likely result in a deterioration in optical qualities.This is partly due to the unpredictable nature of the chemicalinteractions, differences in refractive indexes of the blendedcomponents, and component compatibilities. This makes it quite difficultto achieve a balance of excellent properties across several categoriesof optical and durability characteristics.

The example multilayer structures display an excellent balance ofproperties. Improvements in durability and weatherability were realizedwithout sacrificing the appearance requirements needed (DOI—70 min, 85min preferred; Gloss—75 min @ 60 degrees, 60 min @ 20 degrees) in orderto achieve a “Class A” finish on parts of 0% stretch or greater. Theseimprovements enable the multi-layer structures to be used by automanufacturers and others as vehicle panels, bumper fascias, and/orrocker panels, among other uses.

In the example multilayer structures, a combination of several designelements produces the desired balance of excellent properties. Anefficient, reduced-layer structure is employed that does not require anadhesive to bond the layers of the structure together. Like chemistriesin the bonded layers allows the layers to bond to each other at thelayer interface. Coextrusion technology promotes the bonding of layersand provides a smooth finish. Appropriate selection of polyolefins,additives, and pigmentation for each layer also contributes to thebalance of properties. In addition, further processing techniques andadditives are also used to optimize the optical and durabilitycharacteristics of the multilayer structures.

The clear layer, the color layer, and the backing layer of the examplemultilayer structures are permanently bonded by using like chemistries.Like chemistries in this application means belonging to same family ofolefinic hydrocarbons. Each layer is coextruded from a like olefinicmaterial. This results in permanent bonding at each layer interfacebetween the like olefinic materials. By eliminating the adhesive at theinterface, the durability of the multilayer structures is improved. Asmentioned above, the bond at each layer interface is permanent whichresults in a product that does not delaminate when exposed to heat,sunlight, extreme cold, humidity, water immersion, chemicals, and gravelimpact. In contrast, if there were a coextruded adhesive layerinterposed between the layers it would create a structure thatinherently has a “weak link” that could fail and result in delamination.In addition, the example multilayer structures have a ΔL of 2 or less,according to the GM9302P stress whitening resistance standard. An addedbenefit to the adhesive-layer-free structures is that the sheet productbecomes less complex to manufacture.

The clear layer, the color layer, and the backing layer of themultilayer structures are primarily composed of an olefinic material.For example, polypropylene/ethylene copolymer may be used as theolefinic material for each layer.

FIGS. 1 and 2 both show example three-layer coextruded olefinic sheetstructures.

FIG. 1 illustrates an example sheet structure 1 that can be used to makeboth thick and thin sheets. A multilayer structure as thin as 3 mils toas thick as 540 mils may be created according to this sheet structure 1.Multilayer structures of intermediate thicknesses may also be created,for example, 8.5 mils to 540 mil, 20 mils to 450 mil, 50 mils to 300mil, or 150 mils to 250 mils. Relatively thick sheets may be used inapplications where it is desired to thermoform a part directly from thesheet itself, or thinner sheets may be desirable to thermoform a shellthat is suitable to be backfilled via injection molding to achieve thefinal thickness. Other processes that can be used with this type ofsheet/film structure include compression molding and simultaneousin-mold thermoforming/injection backfill processes.

The clear layer 3 is 1 to 20 mils in thickness, for example, 2.5 to 20mils, 3.0 to 15 mils, or 5.0 to 10 mils. It is primarily made of apolyolefin, such as a polypropylene/ethylene copolymer. An examplepolypropylene/ethylene copolymer for use in the clear layer 3 has amonomer ratio of 0.5-12% ethylene, such as 1-7%, 2-10%, or 3-7%ethylene. The example polypropylene/ethylene copolymer may be isotactic,such as greater 70%, greater 80%, or greater than 90% isotactic and havea random microstructure. The crystallinity of the examplepolypropylene/ethylene copolymer may be greater than 60%, such asgreater than 70%, or greater than 90%. The example copolymer may have aRockwell hardness of R80 or greater, such as R100 or greater, or R105 orgreater. The melting point of the example copolymer is greater than 155°C., such as, 156° C. to 300° C., 156° C. to 170° C., or 156° C. to 165°C. The example polypropylene/ethylene copolymer may have a flexuralmodulus of greater than 1850 MPa, such as 1900 to 2500 MPa, or 2000 to2100 MPa. A blend of polyolefins may also be employed in the clear layer3; for example, a blend of majority isotactic polyolefin and a minorityof syndiotactic polyolefin or atactic polyolefin. Example isotacticpolyolefins include those sold under the following trade names: INSPIRE404 polypropylene (Dow), CLYRELL RC514 L (LyondellBasell), INSPIRE 117polypropylene (Dow), SR257M (LyondellBasell), 6289MZ (Total), 6D83K(Dow), and PRISMA 3410 polypropylene (Braskem). Example syndiotacticpolyolefins include those sold under the following trade names: TOTALPolypropylene 1251 (2 MI, 6.9% Haze, 130° C. melt point) and TOTALpolypropylene 1471 (4 MI, 4.8% Haze, 130° C. melt point). Anotherexample polyolefin is NOTIO from Mitsui Chemicals (Haze 4-7%, Melt point100° C.-135° C.). An example atactic polypropylene is FF018F from Sunoco(1.8 Melt Flow g/10 min at 230 C with 2.16 kg weight). Ametallocene-based copolymer or homopolymer of propylene may also beused. INSPIRE 404, for example, is a highly isotactic, highlycrystalline polypropylene/ethylene copolymer containing about 1-7%ethylene monomer. It has a flexural modulus of 2070 MPa (⅛ inch bar), amelting point of 156° C., an enthalpy of melting of 96 J/g, and aRockwell hardness of R105 hardness. Additives, such as UV stabilizer,e.g. CYASORB THT 7001 (Cytec Industries), Antioxidants, e.g. HOSTANOXPEP-Q (Clariant), and slip agents, e.g. CRODAMIDE ER (Croda), may alsobe added to the polyolefin.

The clear layer 3 should have a light transmittance of 85-100%, such as88-100%, or 90-100%. It should also have a haze of no greater than 10%,such as no greater than 8%, no greater than 5%, no greater than 2.5%, orno greater than 1.0%. For certain applications it may be desirable toinclude a small amount of pigment or special effects in the clear layer3.

The color layer 5 is 1 to 20 mils in thickness, for example 3.0 to 20mils, 4.0 to 15 mils, or 5.0 to 10 mils. The color layer 5 is primarilymade of a polyolefin, such as polypropylene/ethylene copolymer.Preferably, the clear layer 3 and the color layer 5 will have likechemistries, that is, they will be of the same type of polyolefin andsimilar enough in properties that when coextruded as layers they willbecome chemically bonded at the clear/color layer interface 4. As such,an example polypropylene/ethylene copolymer for use in the color layer 5has a monomer ratio of 0.5-12% ethylene, such as 2-10%, or 3-7%ethylene. The example polypropylene/ethylene copolymer may also beisotactic, such as 60-90%, or 70-85% isotactic and have a randommicrostructure. The crystallinity of the example polypropylene/ethylenecopolymer may be greater than 60%, such as greater than 70%, or greaterthan 90%. The example copolymer may have a Rockwell hardness of greaterR100, such as R105 or greater. The melting point of the examplecopolymer is greater than 155° C., such as 156° C. to 300° C., 156° C.to 170° C., or 156° C. to 165° C. The example polypropylene/ethylenecopolymer may have a flexural modulus of greater than 1000 MPa, such asgreater than 1850 MPa, for example as 1900 to 2500 MPa, or 2000 to 2100MPa. A blend of polyolefins may also be employed in the color layer 5;for example, a blend of majority isotactic polyolefin and a minority ofsyndiotactic or atactic polyolefin. Example isotactic polyolefinsinclude those sold under the following trade names: INSPIRE 404polypropylene (Dow), CLYRELL RC514 L (LyondellBasell), INSPIRE 117polypropylene (Dow), SR257M (LyondellBasell), 6289MZ (Total), 6D83K(Dow), and PRISMA 3410 polypropylene (Braskem). Example syndiotacticpolyolefins include those sold under the following trade names:Polypropylene 1251 (Total Petrochemicals) (2 MI, 6.9% Haze, 130° C. meltpoint) and Polypropylene 1471 (Total Petrochemicals) (4 MI, 4.8% Haze,130° C. melt point). Another example polyolefin is NOTIO from MitsuiChemicals (Haze 4-7%, melt point 100° C.-135° C.). An example atacticpolypropylene is FF018F from Sunoco (1.8 Melt Flow g/10 min at 230 Cwith 2.16 kg weight). A metallocene-based homopolymer or copolymer ofpropylene may also be used. Additives, such as UV stabilizer, e.g.CYASORB THT 7001, Antioxidants, e.g. HOSTANOX PEP-Q (Clariant), and slipagents, e.g. CRODAMIDE ER (Croda), may also be added to the polyolefin.

The color layer 5 contains pigment, including opaque pigments,translucent pigments, and special effect pigments such as metal flake,pearlescent, fluorescent, phosphorescent, & mirrored glass. Typically,the color layer 5 will be essentially opaque, such as 10% to 0%, 5% to0.1%, or 1% to 0.01% light transmittance.

Regarding the pigmentation of the color layer 5 (and other polyolefinlayers when desired), the pigment is introduced into the layer 5 as apigment/carrier pre-dispersion. The carrier and pigment are mixed in apre-dispersion, and then added to the color layer 5 polyolefin beforecoextrusion. The carrier is a polymer resin that is selected based onits ability to mix well with the polyolefin and pigment and notnegatively affect the properties of the structure, during or afterprocessing. Pigments compatible with the pigment pre-dispersionsdisclosed herein include organic and inorganic pigments. Examples of thetypes of pigments that can be included in such a pigment pre-dispersioninclude, but are not limited to, carbon black, titanium dioxide, zincoxide, calcium carbonate, black iron oxide, red iron oxide, yellow ironoxide, green iron oxide, mixed metal oxides, bismuth vanadate,phthalocyanine blue, phthalocyanine green, quinacridone reds,anthraquinone, perylene reds, polyazos, or mixtures thereof. Generally,organic pigments are smaller and more difficult to disperse thaninorganic pigments. Examples of resins compatible with polyolefins foruse in the claimed pigment pre-dispersions include, ethylene/acrylicacid copolymer waxes, ethylene/acrylic acid copolymer resins, ethylmethyl acrylate copolymer, and polypropylene/ethylene copolymers, suchas TC-110 EMA (Exxon Mobil), AC540 wax (Honeywell), INSPIRE 404, andPRIMACOR 1410 (Dow).

Many factors can affect the choice of a carrier resin for use in apigment pre-dispersion. Specifically at issue is the compatibility of acarrier resin with the polyolefin into which it will be blended. Therefractive index of a carrier resin compatible with a polyolefin may bevery close to the refractive index of the polyolefin, e.g., within 0.005of the refractive index of the polyolefin (sodium-D filter at 20° C.).Typically, it is advantageous to select a carrier resin with a melt flowrate that is greater than or equal to the melt flow rate of thepolyolefin when measured at the same temperature and load as thepolyolefin. Melt flow rate may be measured, for example, according toASTM D1238. Furthermore, a carrier resin should also be compatible andmiscible with the polyolefin into which it will be blended. Theappearance properties of the final product improve as the compatibilitybetween the carrier resin and the polyolefin increases.

The particle size of the pigment should generally be minimized tooptimize dispersion of the pigment in the polyolefin. As differentpigments are unique compounds having widely varying sizes and molecularproperties, there is no single size that can be suggested as optimal.Generally, the quality of the dispersion achieved upon mixing a pigmentpre-dispersion with a polyolefin will be improved with smaller pigmentparticles. Typically, pigment particle sizes in a pigment pre-dispersionof less than or equal to about 25 micrometers are capable of being welldispersed. Thus, the pigments used in the multilayer structure shouldhave a particle size of less than or equal to about 25 micrometers, suchas 25 micrometers, 15 micrometers, or 10 micrometers.

The pre-dispersion can be made as described in the co-owned U.S.application Ser. No. 11/592,883, titled, “Ionomer Pigmentation,” whichis hereby incorporated by reference.

The pigment pre-dispersion may be added to the polyolefin as thepolyolefin is processed in an apparatus such as an extruder. The pigmentpre-dispersion can be pre-mixed with polyolefin pellets or powder priorto the polyolefin being added to the processing apparatus. Additionally,the pigment pre-dispersion can be let down into an intermediate carrierand this intermediate mixture can then be blended with the polyolefin.If let down into an intermediate carrier, the pigment pre-dispersionlevel can be, for example, about 25% to about 50% of the intermediatemixture. The intermediate mixture may then be mixed with a polyolefin ata level, for example, of about 2% to about 10% of the polyolefin.

The example backing layer 7 of FIG. 1 is 1 to 500 mils in thickness, forexample 3 to 500 mils, 10 to 300 mils, or 100 to 200 mils. The examplebacking layer 7 is primarily composed of a thermoplastic polyolefin,such as polypropylene/ethylene copolymer. The thermoplastic polyolefinis preferably of a random microstructure, and may be exclusive of blockcopolymers. Example random isotactic polyolefins include high-impactcopolymers, for example those having 7 to 30% ethylene homo or copolymercontent, such as Pro-Fax 7823 PP (LyondellBassell). Other example randomisotactic polyolefins include those sold under the following tradenames: INSPIRE 404 polypropylene (Dow), CLYRELL RC514 L(LyondellBasell), INSPIRE 117 polypropylene (Dow), SR257M(LyondellBasell), 6289MZ (Total), 6D83K (Dow), and PRISMA 3410polypropylene (Braskem). Example random syndiotactic polyolefins includethose sold under the following trade names: Total Polypropylene 1251 (2MI, 6.9% Haze, 130° C. melt point) and Total Polypropylene 1471 (4 MI,4.8% Haze, 130° C. melt point). Another example polyolefin is NOTIO fromMitsui Chemicals (Haze 4-7%, melt point 100° C.-135° C.). Ametallocene-based homopolymer or copolymer of propylene may also beused.

The example backing layer also may contain an elastomer, such as, forexample, ethylene alpha-olefin copolymers where the alpha-olefin portioncan contain 3-20 carbon atoms. Examples of such materials include butare not limited to ethylene octene copolymer, ethylene butene copolymer,ethylene hexene copolymer, ethylene heptene copolymer. These type ofalpha olefins represent the following PE families: LDPE, VLDPE, ULDPE.Additional elastomers include, but are not limited to, ethylenepropylene copolymer, ethylene propylene diene terpolymer, ethylenealpha-olefin diene terpolymer, styrenic block copolymer includingstyrene-butadiene-styrene and styrene-ethylene-propylene-styrene. Thevery low density polyethylene rubber may have a density of 0.75 to 0.95g/cm³, such as about 0.88 g/cm³. Preferably, the backing layer 7 and thecolor layer 5 will have like chemistries, e.g. olefinic. An examplebacking layer 7 includes 40-95%, 60-80%, such as 55-70%, of apropylene/ethylene copolymer, the propylene/ethylene copolymer may havea monomer ratio of 0.5-12% ethylene, such as 1-7%, 2-10%, or 3-7%ethylene. The elastomer component when present may make up 50% or lessof the backing layer, such as 5-40%, 10-35%, or 6-10%.

A filler, such as talc may constitute 0-40%, such as 20-30%, or 22-28%of the example backing layer. Furthermore, various other additives suchas process aids, dispersing aids, UV stabilizers, antioxidants, andnucleators may also be utilized in the backing layer in small amounts,such as 0.001% to 10%, 0.01% to 5.0%, or 0.1 to 3.5%. Examples of suchadditives include TR016 wax (Struktol) (process aid & dispersing aid),CHIMASSORB 119 (Ciba) (UV stabilizer), SYNPRO 12B calcium stearate(Ferro) (process aid & dispersing aid), IRGANOX 3114 (Ciba)(antioxidant), HOSTANOX PEP-Q (Clariant) (antioxidant), VANOX ZMTI (R.T.Vanderbilt) (antioxidant), and HPN 20E (Milliken) (nucleator). Thebacking layer 7 may also include pigment and/or effect materials in someapplications.

FIG. 2 shows an example sheet structure that is similar to examplestructure 1 shown in FIG. 1, however, the sheet structure of FIG. 2 is amultilayer tape structure 10. Although the example multilayer tapestructure 10 itself is coextruded, the tape structure 10 may be appliedto a substrate during a lamination process. In this case, the multilayertape structure 10 would be laminated to another substrate prior to,during, or after the forming of an article. In order to achieve goodadhesion after lamination, the backing layer 17 in this structure maycontain an additional adhesive component that will have a lower meltingpoint compared to the other existing olefinic ingredients. Thelamination may be by melt lamination or by an additional laminatedadhesive layer. Examples of laminated adhesive layer includepressure-sensitive tape, roll-applied adhesive, and two-sided tape. Itis also possible to omit the adhesive component if the backing layer 17will adhere to a desired substrate sufficiently without the adhesive. Asadhesive components are added to the backing layer 17, the addition of arelease liner, such as the mask layers described in the commonly ownedWIPO Publication WO 2006/014281, titled “Co-extruded Mask Layer,” whichis hereby incorporated by reference, may be helpful in order to preventthe roll from sticking to itself. A multilayer tape structure 10 as thinas 3 mils to as thick as 25.0 mils, such as 5.0 mils to 25.0 mils may becreated. Multilayer tape structures 10 of intermediate thicknesses mayalso be created, for example, 10.0 to 20.0 mil, or 12.0 to 18.0 mils.

The example clear layer 13 of FIG. 2 is 1 to 10.0 mils in thickness, forexample 2.0 to 10.0 mils, 3.0 to 8.0 mils, or 4.0 to 6.0 mils.Otherwise, the example clear layer 13 of the tape structure 10 isessentially the same as the example clear layer 3 of FIG. 1, describedabove.

The example color layer 15 of FIG. 2 is 1 to 10 mils in thickness, forexample 2.0 to 10.0 mils, 3.0 to 8.0 mils, or 4.0 to 6.0 mils.Otherwise, the example color layer 15 of the tape structure 10 isessentially the same as the example color layer 5 of FIG. 1, describedabove.

The example backing layer 17 of FIG. 2 is 1 to 5.0 mils in thickness,for example 1.5 to 4.5 mils, or 2.0 to 4.0 mils. The example backinglayer 17 of the tape structure 10 is essentially the same as the examplebacking layer 7 of FIG. 1, described above, except it contains anadhesive as part of the polymeric blend. The adhesive component may beused in practically any weight percentage in the backing structure, forexample, 60 to 100%, 20-60%, 30-50%, or 35-45%. The adhesive componentmay be olefinic polymers, or copolymers such as polypropylene/ethylenecopolymers with a high level of ethylene monomer content, and a lowmelting point, for example, ethylene alpha-olefin copolymers where thealpha-olefin portion can contain 3-20 carbon atoms. Examples of suchmaterials include, but are not limited to, ethylene octene copolymer,ethylene butene copolymer, ethylene hexene copolymer, ethylene heptenecopolymer. These type of alpha olefins represent the followingpolyethylene families: LDPE, VLDPE, ULDPE. Additional elastomersinclude, but are not limited to, ethylene propylene copolymers, ethylenepropylene diene terpolymer, ethylene alpha-olefin diene terpolymer,styrenic block copolymers including styrene-butadiene-styrene,styrene-ethylene-propylene-styrene and the like, a particular example ofethylene-propylene elastomer is VERSIFY 2300 (Dow). The adhesivecomponent could also include, but is not limited to, other olefinic ornon-olefinic materials such as ethylene-acrylate-GMA terpolymers,ethylene butyl (or methyl or hexyl)acrylate copolymers, EVA, ester andether based urethanes, ethylene acid copolymers, and maleic anhydridegrafted copolymers.

Varying the type of adhesive component in polymeric blend allows themultilayer structure to be laminated to different substrates, including,but not limited to: polypropylene, TPO, polyethylene, a polymeric blendor alloy containing polypropylene or polypropylene in it, ABS, ABScontaining blends or alloys, acrylic, polycarbonate, polycarbonatecontaining blends or alloys, metal, glass, wood, ceramic, thermosetplastics, and composites. The adhesive layer 17 may be provided withpigment and/or effect material.

FIGS. 3 and 4 depict the four-layer structure 20, 30 counterparts of thethree-layer structures 1, 10 of FIGS. 1 and 2. As such, the four-layerstructures 20, 30 are used in substantially the same manner as describedfor FIGS. 1 and 2, respectively, and are similar in composition, exceptas noted below. The four-layer structures 20, 30 in FIGS. 3 and 4 eachhave a clear layer 23, 33, a color layer 25, 35, and a backing layer 27,37. The structures of FIGS. 3 and 4, however, differ from the structureof FIGS. 1 and 2 in that each has a translucent color layer 29, 39between the clear 23, 33 and color layers 25, 35. The translucent colorlayer 29, 39 is primarily made of a polyolefin, such aspolypropylene/ethylene copolymer. An example polypropylene/ethylenecopolymer for use in the translucent color layer 29, 39 has a monomerratio of 0.5-12% ethylene, such as 2-10%, or 3-7% ethylene. The examplepolypropylene/ethylene copolymer may also be isotactic, such as 60-90%,or 70-85% isotactic and have a random microstructure. The crystallinityof the example polypropylene/ethylene copolymer may be greater than 60%,such as greater than 70%, or greater than 90%. The example copolymer mayhave a Rockwell hardness of greater R100, such as R105 or greater. Themelting point of the example copolymer is greater than 155° C., such as156° C. to 300° C., 156° C. to 170° C., or 156° C. to 165° C. Theexample polypropylene/ethylene copolymer may have a flexural modulus ofgreater than 1000 MPa, such as greater than 1850 MPa, 1900 to 2500 MPa,or 2000 to 2100 MPa. A blend of polyolefins may also be employed in thetranslucent color layer 29, 39; for example, a blend of majorityisotactic polyolefin and a minority of syndiotactic or atacticpolyolefin. Example random isotactic polyolefins include those soldunder the following trade names: INSPIRE 404 polypropylene (Dow),CLYRELL RC514 L (LyondellBasell), INSPIRE 117 polypropylene (Dow),SR257M (LyondellBasell), 6289MZ (Total), 6D83K (Dow), and PRISMA 3410polypropylene (Braskem). Example random syndiotactic polyolefins includethose sold under the following trade names: Polypropylene 1251 (Total)(2MI, 6.9% Haze, 130 C melt point) and Polypropylene 1471 (Total)(4 MI,4.8% Haze, 130 C melt point). Another example polyolefin is NOTIO fromMitsui Chemicals (Haze 4-7%, Melt point 100 C-135 C). An example atacticpolypropylene is FF018F from Sunoco (1.8 Melt Flow g/10 min at 230 Cwith 2.16 kg weight). A metallocene-based homopolymer or copolymer ofpropylene may also be used. This translucent color layer may be used tocreate various special effects such as metal flake, pearlescent,fluorescent, phosphorescent, and mirrored glass and/or improve the depthof color for the underlying opaque color layer. The polyolefin thatmakes up the translucent color layer may be of the same chemistry as theclear 23, 33 and color layers 25, 35 to promote adhesive-free bonding atthe layer interfaces 24, 34, 26, 36, 28, 38.

The translucent color layer 29, 39 does not require that onlytranslucent pigments are used therein. In this case, “translucent” ismeant to refer to the percent loading of color used in the translucentlayer 29, 39. All pigments used in the color layer 25, 35 can also beused in the translucent layer 29, 39, but are used in lower amounts(relative to the underlying essentially opaque color layer 25, 35) inorder to maintain some level of the base resin clarity.

Regarding the example four-layer structure of FIG. 3, the structure 20may be as thin as 4.0 mils to as thick as 560 mil, such as 11 mils to560 mils. Multilayer structures of intermediate thicknesses may also becreated, for example, 20 mils to 450 mil, 50 mils to 300 mil, or 150mils to 250 mils. Relatively thick sheets may be used in applicationswhere it is desired to thermoform a part directly from the sheet itself,or thinner sheets may be desirable to thermoform a shell that issuitable to be backfilled via injection molding to achieve the finalthickness. The translucent layer 29 may be 1 to 20 mils in thickness,such as 2.5 to 20 mils, 5.0 to 15 mils, or 7.0 to 12.0 mils.

Regarding the example four-layer tape structure 30 of FIG. 4, thestructure 30 may be as thin as 4 mils to as thick as 35.0 mils.Multilayer structures of intermediate thicknesses may also be created,for example, 7 mils to 35 mils, 8.0 mils to 30.0 mils, 10 mils to 20.0mils, or 12.0 mils to 18.0 mils. The translucent layer 39 is 1 to 10mils in thickness, for example 2.0 to 10 mils, 3.0 to 8.0 mils, or 4.0to 6.0 mils. As with the tape structure 10 of FIG. 2, the four-layertape structure 30 would be laminated to another substrate prior to orduring the forming of an article. In order to achieve good adhesionafter lamination, the backing layer 37 in this structure 30 may containan additional adhesive component that will have a lower melting pointcompared to the other existing olefinic ingredients.

FIG. 5 depicts an example two layer structure 40 that includes a clearpolyolefin layer 43 over a colored backing layer 47. The clear layer 43has the same characteristics as the example clear layer 3 of FIG. 1,except that it is coextruded with and permanently bonded directly to thecolored backing layer 47 at a layer interface 44. The colored backinglayer 47 is the same as the backing layer 7 of FIG. 1, except it isprovided with pigment and/or effect materials. Carrier resins may alsobe used to incorporate the pigment and/or effect materials into thecolored backing layer 47. Example carrier resins, pigments, and effectmaterials may be selected from those listed above in the discussion ofthe color layer 7 of FIG. 1. The carrier resin, however, should becarefully selected to be compatible with the majority component polymerof the colored backing layer 47. That is, the carrier resin should havesimilar melt flow rate, refractive index, and be miscible in themajority component polymer. The pigment and/or effect materials may beincorporated into the colored backing layer 47 in an amount of 0.0001%to 30%, for example, 0.01% to 20%, 1.0% to 10%, or 0.0001% to 0.01%.

In an alternative example, the clear polyolefin layer 43 may be replacedwith a colored layer as described above having pigments and/or effectmaterials.

Some examples of different formed products in which this two layerstructure is used include: RV exterior wall panels, heavy truck and RVair cones, fenders or body panels for agricultural vehicles, and truckfarings.

The structures 1, 10, 20, 30, 40 shown in FIGS. 1-5 may be used with orwithout a mask layer, such as a protective mask, forming mask, orcombination of protective/forming mask, for example, the mask layersdescribed in WIPO Publication WO 2006/014281. The mask layer could belaminated onto or coextruded with the structures illustrated in FIGS.1-4.

In order to improve or modify the performance of an individual layer orthe structure as a whole, each layer shown in FIGS. 1-5 may containadditive ingredients from the following list in any combination. Thelist is as follows:

Antioxidants

UV stabilizers

Waxes as Property Modifiers

Lubricants

Antistats

Process Aids

Dispersion Aids

Flame Retardants

Smoke Suppressors

Foaming Agents

Colorants (pigments, dyes, all special effect additives)

Antimicrobials

Antiblock Agents

Fiber Additives

Plasticizers (e.g. polypropylene plasticizers such as Elevast orpolyethylene-glycol)

Antifog Agents

Clarifying Agents

Nucleating Agents

Acid Scavengers

Low Temperature Impact Modifiers

Fillers (inorganic & wood)

Gloss Agents

Gloss Reducing Agents

Scratch Mar Additives

Stress Whitening Modifiers

Surfactants

Silicone, Siloxanes, Organo-Modified Siloxanes, or Silicone GraftCopolymers (e.g., Evonik Tegomer which may contain alkyl, epoxide,hydroxy, amino, carboxyl, and/or acrylate organic substituents)

Functional grafted polypropylene modifiers (e.g. acid graftedpolypropylene, maleic anhydride grafted polypropylene, and ionicfunctional grafted polypropylene)

In particular, one or more clarifying agents may be added to polymersthat are already clarified by various methods or the clarifying agentsmay be added to non-clarified polymers. Stress whitening agents may beadded to improve blush resistance.

The aforementioned additives may also be utilized in each layer inrelatively small amounts, such as 0.0001% to 10%, 0.0001% to 0.001%,0.0001 to 1%, 1% to 5%, and 5% to 10%, and for fillers, fibers,retardants, functional grafted polypropylene modifiers, and smokesuppressor additives, up to 50%, such as up to 40%, or 10-30%.

The example multilayer structures are not substantially oriented eitheraxially or biaxially by stretching. By not substantially oriented, it ismeant that the polymers are not purposely stretched to induceorientation that would affect the physically properties of the material.The multilayer structure may have a flexural modulus of 1000 MPa orgreater, such as 1500 to 7000 MPa, 1700 to 3000 MPa, 3000 to 6000 MPa,or 2500 to 5500 MPa.

The example multilayer structures display excellent optical qualities.The example multilayer structures have a distinction of image (DOI) ofat least 70, such as 75 or greater, 85 or greater, 90 or greater, and 95or greater. Furthermore, the multilayer structures have a gloss of 75 orgreater at a 60° angle, such as 85 or greater, 90 or greater, and 95 orgreater. The multilayer structures also have a gloss of 60 or greater ata 20° angle, such as 70 or greater, 80 or greater, and 85 or greater.

The example multilayer structures also posses excellent durability andmar resistance, exemplified by several tests required by automanufacturers (see Table 2 below). For instance, the multilayerstructures will pass a five-finger scratch and mar resistance testdefined by GMW 3943. The structures also exhibit no gauze imprint at 70°C. minimum under a 500 g load applied over a 40 mm diameter for twohours. Furthermore, the multilayer structures show no signs of glossloss, staining, or surface swelling at 70° C. with exposure to methanol,motor oil, lithium grease, and egg albumin.

The multilayer structures can be thermoformed into formed products, suchas, for example, an automobile bumper or other exterior trim panel. Sucha part can be made from a multilayer structure that is thick enough toprovide sufficient structural stability to be used alone. Furthermore,the multi-layer structure can be injection molded from behind withadditional polymer material to provide support to the multilayerstructure. The pigmented polyolefins with their minimized pigmentparticle size are able to maintain color uniformity and opacity in highdraw regions created during thermoforming.

The layers of the multilayer structures are coextruded and include thoselayers shown in FIGS. 1-5 and described herein. Additional co-extrudedlayers can include, but are not limited to, polymers such aspolypropylene, polypropylene copolymer, polyethylene, polyethylenecopolymer, polyamide, polyester, ABS, styrene terpolymer, andpolyurethane.

The polyolefin layers and multilayer films as described herein may beexposed to various structure modifying treatments to further enhanceaspects of physical performance. These products may, for example, besubjected to corona discharge treatment, ozone treatment, lowtemperature plasma treatment which incorporates either oxygen ornitrogen gas, glow plasma treatment, reverse sputtering treatment,oxidation treatment using chemicals, UV curing, e-beam irradiation,gamma beam irradiation, x-rays and the like. Such treatments may, amongother things, cross-link the polymer structure of the polyolefin layersand the multilayer films. As an example, the multilayer films could beexposed to gamma beam, electron beam, or x-ray radiation at dosinglevels of between 0.1 and 50 meg-rads. These treatments can improve thesurface hardness, scratch resistance, mar resistance, chemicalresistance and/or oxygen/air barrier efficiency of the multilayerstructures while maintaining low haze, high gloss, transparency, anddistinction of image. Additionally, weathering performance can bemaintained or enhanced and material memory can be maintained. Thesetreatments may also improve the adhesion properties of the tapestructures 10, 30 to various substrates.

The improvements realized in the multilayer structures described hereinin both design and durability performance allow them to be used in avariety of markets which require a “Class A” finish, such as:

Motor Vehicles

Light/Consumer Automotive

Heavy Trucks

RV

Agriculture

ATV's

Motorcycles

Snowmobiles

Jet Skis

Marine

Farm Machinery

Signage

Appliances

Consumer Electronics.

Example articles the multilayer sheets could be formed into include:

Bumper fascias

Rocker panels

Cell-Phone covers

Computer housings

Motor covers

Fenders

Heavy truck fairings

Running boards

RV wall panels

Appliance housings.

FIGS. 6 and 7 show example cross-sections of vehicle body panelsconstructed of the multilayer structure of the present disclosure. InFIG. 6, the multilayer film has a clear layer 53, a color layer 55, anda backing layer 57, and the multilayer film is laminated onto a rigidsubstrate 59. In FIG. 7, the multilayer structure 60 has a clear layer63, a color layer 65, and a backing layer 67. The multilayer structure60 is thick and rigid enough to be a vehicle body panel without anadditional rigid substrate. The translucent layer discussed above mayalso be used in combination with or in place of the colored layer onvehicle body panels. Also, the colored backing layer may be used inplace of the backing layer and with only a clear layer on top in vehiclebody panels.

In an additional example, the structures 1, 10, 20, 30 in FIGS. 1-4 andstructures 40, 50, and 60 in FIGS. 5-7 utilize regrind as an additionallayer adjacent to the backing layer or as a component of the backinglayer. As explained below, the example backing layer providessignificant and unexpected advantages over backing layers that mixregrind and virgin polymer in one layer.

Thermoforming TPO sheet is typically difficult due to the material'sinherently weak melt strength. Inadequate melt strength during heatingresults in excessive “sheet sag,” which in turn can cause variousdefects during forming of the part. Defects include excessive “webbing”in tight corners, surface “tears” in areas of high stretch, andnon-uniform wall thickness. Significant variation in wall thicknessthroughout a part can cause excessive warping and/or reduced physicalproperties.

During sheet production, the melt strength of TPO is further compromiseddue to the addition of regrind which causes an increase in the severityof the above mentioned defects. The addition of regrind is performed inorder to control costs by minimizing waste and reducing the overall rawmaterial cost of the final part. Although the economics improve with theaddition of regrind, the melt strength, sag resistance, and otherproperties of the sheet are significantly reduced.

It was unexpectedly discovered that the reduction of melt strength andsag resistance due to the addition of regrind can be significantlyreduced by changing the structure of the TPO sheet.

As shown in FIGS. 8 and 9 the thermoplastic polyolefin backing layer hasmultiple layers as components. There is a separate layer of virginthermoplastic polyolefin material (Layer A) and a separate layer ofregrind thermoplastic polyolefin material (Layer B). FIG. 8 shows anexample sheet structure 70 with an ABA multilayered backing layerstructure and FIG. 9 shows an example sheet structure 80 with an ABbacking layer structure 80.

The example sheet structure 70 in FIG. 8 has an ABA backing layer madeup of a first A layer 71, a second A layer 73, and a B layer 72 disposedbetween the first and second A layers 71, 73. First A layer 71 isadjacent to one side of the B layer 72 and the second A layer 73 isadjacent to the opposite side of the B layer 72. The ABA backing layeris combined with an upper section 75 that comprises a clear layer andoptionally a translucent and/or color layer, as those layers aredescribed above and are depicted in structures 1, 10, 20, 30, 40, 50, 60shown in FIGS. 1-7. The first A layer 71 is adjacent to the uppersection 75.

The polymeric base for first A layer 71 and the second A layer 73 of theexample sheet structure 70 of FIG. 8 is 100% virgin thermoplasticpolyolefin. Virgin thermoplastic means a thermoplastic that has not beenreprocessed and/or previously used in another product. The thermoplasticpolyolefin may be selected from the thermoplastic polyolefins describedabove for the backing layer 7 of FIG. 1. Additives may also be includedas described herein for the backing layer.

The first A layer 71 is, for example, 5% to 45% of the total thicknessof the ABA backing layer, such as 10 to 35%, 5 to 20%, or 25 to 45% ofthe total backing layer thickness. The entire example ABA backing layerstructure is 3.0 to 500 mils, so the first A layer 71 may be 0.15 milsto 225 mils, such as 5 to 10 mils, 10-80 mils, or 20 to 150 mils. Thesecond A layer 73 has the same range of thicknesses, however, itsthickness is independently selected from the thickness of the first Alayer 71.

The polymeric base for the B layer 72 is 100% regrind polyolefinmaterial (meaning a polyolefin that has been previously used and/orreprocessed). If desired for certain applications, the B layer 72 mayalso be a mixture of regrind and virgin polymeric material. For example,the polymeric base for the B layer may comprise 10 to 99% regrind, suchas 10 to 49%, 51 to 99%, or 25 to 75% regrind material, whereas theremainder of the polymeric base is virgin polyolefin material.

The regrind material is produced from sources such as trim scrap,products that do not meet quality control or specifications, or variousother sources that would otherwise be waste materials. The originalpolymer used in the regrind material may, for example, be selected fromthe thermoplastic polyolefins described above for the backing layer 7 ofFIG. 1. The original material used for the regrind material may alsoinclude additives as described herein for the backing layer. In oneexample, the regrind material is miscellaneous polypropylenehomopolymers and copolymers with talc filler, colorants, andstabilizers.

The B layer 72 is, for example, 10-90% of the total thickness of the ABAbacking layer, such as 10 to 49%, 51 to 90%, or 20 to 60% of the totalbacking layer thickness. The entire example ABA backing layer structureis 3.0 to 500 mils, so the B layer 72 may be 0.3 mils to 450 mils, suchas 5 to 20 mils, 20-120 mils, or 40 to 300 mils.

In an alternate example, the first A layer 71 and optionally the secondA layer 73 also include a pigment to supply the layer with a desiredcolor. This colored backing layer is particularly suitable for use withan upper section 75 that includes only a clear layer. This can beconsidered a two-layer structure as described above and shown in FIG. 5,although the backing layer is divided into three separate layers.

The example sheet structure 80 shown in FIG. 9 has an AB backing layermade up of an A layer 81 and a B layer 83. The AB backing layer iscombined with an upper section 85 that comprises a clear layer andoptionally a translucent and/or color layer, as those layers aredescribed above, and are depicted in structures 1, 10, 20, 30, 40, 50,60 shown in FIGS. 1-7. The A layer 81 is adjacent to the B layer 83 onone side and is adjacent to the upper section 85 on the other side.

The A layer 81 and B layer 83 are composed of the same materials asdisclosed for the ABA layer example shown in FIG. 8. Coloring may alsobe added to the A layer 81 as described above, particularly when the ABbacking layer is used in conjunction with just a clear layer in theupper section 85.

The A layer 81 is, for example, 10-90% of the total thickness of the ABbacking layer, such as 20-60%, 10 to 49%, or 51-90% of the total backinglayer thickness. The entire example AB backing layer structure is 3.0 to500 mils, so the A layer 81 may be 0.3 mils to 450 mils, such as 5 to 20mils, 20-120 mils, or 40 to 300 mils.

The B layer 83 is, for example, 10-90% of the total thickness of the ABbacking layer, such as 20-60%, 10 to 49%, or 51-90% of the total backinglayer thickness. The entire example AB backing layer structure is 3.0 to500 mils, so the B layer 83 may be 0.3 mils to 450 mils, such as 5 to 20mils, 20-120 mils, or 40 to 300 mils.

The ABA and AB backing layers may be formed by coextrusion. The ABA andAB backing layers can be coextruded with the upper section that includesa clear layer and optionally a color and/or translucent layer. Inanother example, further thermoplastic polyolefin layers may be added.For example, the backing layer may be structured as an ABABA layeredstructure.

The example sheet structure 70, 80 may also be used in conjunction withupper sections 75, 85 that comprise chemistries other than thepolyolefin layers described above. For example, the upper sections 75,85 may comprise polymeric components such as acrylic, ionomer,fluoracrylic, fluoropolymers, cast-fluoroacrylic, polystyrene,polyethylene, polycarbonate, acrylic styrene acrylonitrile (ASA), ormixtures thereof. These alternative upper section chemistries could alsobe extruded or laminated onto the ABA backing layer. In certainembodiments the upper sections 75, 85 could even be paint.

Examples 1-6

Example 1 is a prospective, generic example, and is set forth todemonstrate an example range of different ingredients that may be addedto each layer of the multilayer structure. The optimal concentration andpresence of these ingredients will vary based on the color and type ofpigment desired. Other application specific parameters may also affectthe composition of the multilayer structure.

Prospective Generic Example 1 Clear Layer

70-100% Inspire 404 Clear PP* *Inspire 404 PP is a highly isotactic,highly crystalline polypropylene/ethylene copolymer containing about1-7% ethylene monomers, and having a flexural modulus of 2070 MPa (⅛inch bar), 156° C. melting point, 95.6 J/g enthalpy of melting, RockwellC hardness)

0-3.0% UV Stabilizer e.g. Cyasorb THT 7001

0-10.0% Slip Agent e.g. Crodamide ER (an effective amount that does notimpact haze detrimentally)

0-3% Clarifier, e.g. NX20

0-1.0% Antioxidant, e.g. Hostanox Pep-Q

0-1.0% Second Antioxidant, e.g. Irganox 3114

Translucent Color Layer (this Layer is Optional & the Formula Varieswith Color & Special Effects)

60.000-99.000% Polypropylene, e.g. Inspire 404 PP*

0-1.0% Antioxidant, e.g. Hostanox Pep-Q

0-3% Clarifier, e.g. NX20

>0-10.000% pigment &/or special effects

00.000-20.000% Color carrier 1 e.g. LLDPE purchased from LancerDispersions

00.000-20.000% Color carrier 2, e.g. Ethylene Acid Copolymer

00.000-20.000% Color carrier 3, e.g. AC540 Wax

00.000-20.000% Color carrier 4, e.g. Inspire 404 PP

00.000-3.00% UV Stabilizer, e.g. Cyasorb THT 7001

0-1.0% Antioxidant, e.g. Irganox 3114

Color Layer (this Formula Varies with Color & Special Effects)

50.000-95.000% Polypropylene, e.g. Inspire 404 PP*

0-3% Clarifier, e.g. NX20

0-1.0% Antioxidant, e.g. Hostanox Pep-Q

>0-20.000% Pigment &/or special effects

00.000-25.000% Color carrier 1, e.g. LLDPE

00.000-25.000% Color carrier 2, e.g. Ethylene Acid Copolymer

00.000-25.000% Color carrier 3, e.g. AC540 Wax

00.000-25.000% Color carrier 4, e.g. Inspire 404 PP

00.000-3.00% UV Stabilizer, e.g. Cyasorb THT 7001

0-1.0% Second antioxidant, e.g. Irganox 3114

Backing Layer

40-95% Polypropylene, e.g. Pro-Fax 7823 PP** **Pro-Fax 7823 PP is apolypropylene/ethylene copolymer, Rockwell 80R scale, flexural modulusof 1120 MPa by ASTM D790, melting point greater than 120° C.

0-60% Rubber, e.g. DFDB 1088NT VLDPE

0-40% Talc Filler, e.g. Premium HTP Ultra 5 L

0-2% Process aid and dispersing aid, e.g. TR016 Wax

0-3% UV stabilizer, e.g. Chimassorb 119

0-2% Second process aid and dispersing aid, e.g. Synpro 12B CalciumStearate

0-1% Antioxidant, e.g. Irganox 3114

0-1% Second Antioxidant, e.g. Hostanox Pep-Q

0-1% Third Antioxidant, e.g. Vanox ZMTI

0-0.5% Nucleator, e.g. HPN 20E

0-8.000% Pigment or Color Concentrate (A. Schulman)

Examples 2-6 are actual, non-generic examples, optimized for certainpigments.

Example 2 Three-Layer Structure

Clear Layer

96.1% Inspire 404 Clear PP*

00.3% Cyasorb THT 7001 (UV stabilizer)

00.3% Crodamide ER (slip agent)

3% NX20 (Milliken Chemical) (clarifier)

0.300% Hostanox Pep-Q (antioxidant)

Color Layer

90.280% Inspire 404 PP*

3% NX20 (clarifier)

4.000% AC540 Wax (organic pigment carrier)

0.360% TC-110 EMA (inorganic pigment carrier)

0.040% Red Iron Oxide 116M (Nubiola) (pigment)

0.720% Perylene Red 179 229-8436 (Sun Chemical) (pigment)

1.000% DPP Red 254 Cromophtal 2030 (Ciba) (pigment)

0.300% Cyasorb THT 7001 (UV Stabilizer)

0.300% Hostanox Pep-Q (antioxidant)

Backing Layer

61.944% Pro-Fax 7823 PP**

7.680% DFDB 1088NT VLDPE (Dow Chemical)

24.48% Premium HTP Ultra 5 L talc filler (Imi Fabi)

0.576% TR016 Wax (process aid & dispersing aid)

0.288% Chimassorb 119 (UV stabilizer)

0.048% Synpro 12B Calcium Stearate (process aid & dispersing aid)

0.288% Irganox 3114 (antioxidant)

0.288% Hostanox Pep-Q (antioxidant)

0.288% Vanox ZMTI (antioxidant)

0.120% HPN 20E (Milliken Chemical) (nucleator)

4.000% Schulman Gray Color Concentrate (A. Schulman)

Example 3 Four-Layer Structure

Clear Layer

99.1% Inspire 404 Clear PP*

00.3% Cyasorb THT 7001 (UV stabilizer)

00.3% Crodamide ER (slip agent)

00.3% Hostanox Pep-Q (antioxidant)

Translucent Color Layer

98.700% Inspire 404 PP*

0.490% AC540 Wax (organic pigment carrier)

0.210% DPP Red 254 Cromophtal 2030 (pigment)

0.300% Cyasorb THT 7001 (UV Stabilizer)

0.300% Hostanox Pep-Q (antioxidant)

Color Layer

79.400% Inspire 404 PP* 14.000% R104 TiO2 (pigment) (DuPont)

4.796% HB9200 propylene homopolymer (Ineos USA LLC) (pigment carrier)

1.204% Profax 6301 polypropylene (Lyondell Bassell) (pigment carrier)

0.300% Cyasorb THT 7001 (UV Stabilizer)

0.300% Hostanox Pep-Q (antioxidant)

Backing Layer

61.944% Pro-Fax 7823 PP**

7.680% DFDB 1088NT VLDPE

24.48% Premium HTP Ultra 5 L (talc filler)

0.576% TR016 Wax (process aid & dispersing aid)

0.288% Chimassorb 119 (UV stabilizer)

0.048% Synpro 12B Calcium Stearate (process aid & dispersing aid)

0.288% Irganox 3114 (antioxidant)

0.288% Hostanox Pep-Q (antioxidant)

0.288% Vanox ZMTI (antioxidant)

0.120% HPN 20E (nucleator)

4.000% Schulman Gray Color Concentrate (A. Schulman)

Example 4 Four-Layer Structure

Clear Layer

96.1% Inspire 404 Clear PP*

3% NX20(clarifier)

00.3% Cyasorb THT 7001 (UV Stabilizer)

00.3% Crodamide ER (Slip Agent)

0.30% Hostanox Pep-Q (antioxidant)

Translucent Color Layer

94.400% Inspire 404 PP*

3% NX20(clarifier)

1.120% AC540 Wax (organic pigment carrier)

0.480% PR177 (DIC) (pigment)

0.240% Primacor 1410 (pigment carrier)

0.160% 9320J Hi-Lite Sparkle Orange (BASF) (special effects pigment)

0.300% Cyasorb THT 7001 (UV Stabilizer)

0.300% Hostanox (antioxidant)

Color Layer

93.450% Inspire 404 PP*

3% NX20(clarifier)

0.875% AC540 Wax (organic pigment carrier)

0.375% BP1300 (Cabot) (carbon black) (pigment black #7)

2.000% Silver ET-2025 Aluminum Flake (Silberline)

0.300% Cyasorb THT 7001 (UV Stabilizer)

0.300% Hostanox Pep-Q (antioxidant)

Backing Layer

61.944% Pro-Fax 7823 PP**

7.680% DFDB 1088NT VLDPE

24.48% Premium HTP Ultra 5 L (talc filler)

0.576% TR016 Wax (process aid & dispersing aid)

0.288% Chimassorb 119 (UV stabilizer)

0.048% Synpro 12B Calcium Stearate (process aid & dispersing aid)

0.288% Irganox 3114 (antioxidant)

0.288% Hostanox Pep-Q (antioxidant)

0.288% Vanox ZMTI (antioxidant)

0.120% HPN 20E (nucleator)

4.000% Schulman Gray Color Concentrate (A. Schulman)

Example 5 Three-Layer Structure

Clear Layer

96.900% Pristene RM2091*** ***Pristene RM2091 is an metallocene basedisotactic polypropylene/ethylene copolymer, melting point 130° C.,flexural modulus 1000 MPa by ISO 178.

1.000% Hostavin PR-31 (Clariant)

0.150% Hostavin VSU (Clariant)

0.300% Hostanox Pep-Q (antioxidant)

0.300% Irgastab FS-042 (Ciba)

0.350% Tinuvin 328 (Ciba)

1.000% Crodamide ER (slip agent)

Color Layer

90.780% Pristene RM2091***

4.000% AC540 Wax (organic pigment carrier)

0.360% LLDPE (Lancer Dispersions) (inorganic pigment carrier)

0.040% Red Iron Oxide 116M (inorganic pigment)

0.720% Perylene Red 179 229-8436 (organic pigment)

1.000% DPP Red 254 CROMOPHTAL 2030 (organic pigment)

1.000% Hostavin PR-31 (Clariant) (UV additive)

0.150% Hostavin VSU (Clariant) (UV additive)

0.300% Hostanox Pep-Q (antioxidant)

0.300% Irgastab FS-042 (Ciba) (antioxidant)

0.350% Tinuvin 328 (Ciba) (UV additive)

1.000% Crodamide ER (slip agent)

Backing Layer

58.704% Pro-fax 7823 PP**

11.520% DBDB 1088 NT VLDPE (Dow)

24.480% Premium HTP Ultra 5 L Talc (filler)

0.048% Calcium Stearate Synpro 12B 0.518% Irganox 3114 (antioxidant)

0.346% Doverphos F9228 (antioxidant) (Dover Chemical Corp.)

0.288% Chimasorb 119 (UV stabilizer)

0.096% Tinuvin 328 (Ciba) (UV additive)

4.000% Schulman Gray Color Concentrate (A. Schulman)

Example 6 Two-Layer Structure with Colored TPO

Clear Layer

90% Inspire 404 PP*

6.9% RM2091 (LyondellBasell)

1.000% Hostavin PR-31 (UV additive)

0.150% Hostavin VSU (UV additive)

0.300% Hostanox Pep-Q (antioxidant)

0.350% Tinuvin 328 (UV additive)

1.000% Crodamide ER (slip agent)

Colored TPO Layer

62.123% Profax PP7823**

7.640% DFDB 1088 NT VLDPE

24.352% Hi Talc Premium HTP Ultra 5 L

0.048% Synpro 12B calcium stearate (process aid & dispersing aid)

0.516% Irganox 3114 (antioxidant)

0.344% Hostanox Pep-Q (antioxidant)

0.382% Tinuvin XT850 (Ciba) (UV additive)

03095% Tinuvin 328 (UV additive)

4.500% Schulman PX-1657 Ford White P Color Concentrate (A. Schulman)

(All Percentages are by Weight.) Process for Example 2

Clear Layer

First, an additive concentrate was made by feeding the UV stabilizer andslip agent along with about 2.4% by weight (based upon the total weightof the clear layer) of the INSPIRE 404 polypropylene copolymer to a twinscrew extruder. The INSPIRE 404 polypropylene copolymer acts as acarrier resin in this stage of the process. The extruded product is apelletized additive concentrate.

The clear layer was then fabricated by feeding the remainingapproximately 93.7% of the INSPIRE 404 polypropylene copolymer to asingle screw extruder along with the additive concentrate, theclarifier, and the antioxidant. The additive concentrate makes up 3% ofthe total weight of the clear layer.

Color Layer

An additive concentrate was made for the color layer, just as describedabove for the clear layer, except no slip agent is present.

Additionally, a first color concentrate was made by combining water, theorganic pigments (Perylene Red 179 229-8436 and DPP Red 254 Cromophtal2030) and organic pigment carrier (AC540 Wax). The water is displaced bythe addition of the organic pigment carrier during a flushing process,as described in U.S. patent publication 2005/0282962, which is hereinincorporated by reference. A second color concentrate was made by addingthe inorganic pigment and inorganic carrier resin to a mill.

The color layer was then fabricated by feeding the INSPIRE 404polypropylene copolymer to a single screw extruder along with theadditive concentrate and the first and second color concentrates.

Backing Layer

In a separate process, a Farrell Continuous Mixer was loaded withPro-Fax 7823 polypropylene and the DFDB 1088NT very low densitypolyethylene. Talc and the other additives listed in the formula forExample 2 were added also. The product of the mixer was natural TPO inpellet form.

The color concentrate pellets and the natural TPO pellets were thenadded to a single screw extruder, which produced the backing layer.

Coextrusion Setup

The single screw extruders for the clear, color, and backing layers werepositioned so that each layer would be coextruded in a multilayer stack.

Process for Example 3

Clear Layer

The clear layer was made by the process described above in Example 2,but with the formula for Example 3.

Translucent Layer

The color concentrate was made by the same process used to make thecolor layer as described in Example 2, but with the pigment and carrierresin given in the formula above for Example 3.

The translucent layer was then fabricated by feeding the INSPIRE 404polypropylene copolymer to a single screw extruder along with the colorconcentrate, the antioxidant, and the UV additive.

Color Layer

The color layer was fabricated by feeding the INSPIRE 404 polypropylenecopolymer to a single screw extruder along with the two carrier resinsand one pigment, the antioxidant, and the UV additive.

Backing Layer

The backing layer was made by the process described above in Example 2.

Coextrusion Setup

The single screw extruders for the clear, translucent, color, andbacking layers were positioned so that each layer would be coextruded ina multilayer stack.

Process for Example 4

Clear Layer

The clear layer was made by the process described above in Example 2,but with the formula for Example 4.

Translucent Layer

The translucent layer was made by the same process used to make thetranslucent layer as described in Example 3, but with the formula forExample 4.

Color Layer

An additive concentrate was made for the color layer, just as describedabove for the clear layer, except no slip agent is present.

Additionally, a color concentrate was made by combining water, thecarbon black pigment BP1300 and organic pigment carrier (AC540 Wax). Thewater is displaced by the addition of the organic pigment carrier duringthe flushing process, as described in U.S. patent publication2005/0282962.

The color layer was then fabricated by feeding the INSPIRE 404polypropylene copolymer to a single screw extruder along with theadditive concentrate, the color concentrate, and the aluminum flake.

Backing Layer

The backing layer was made by the process described above in Example 2.

Coextrusion Setup

The single screw extruders for the clear, translucent, color, andbacking layers were positioned so that each layer would be coextruded ina multilayer stack.

Process for Example 5

Clear Layer

First, an additive concentrate was made by feeding the UV stabilizer,antioxidant, and slip agent along with about 6.9% by weight (based uponthe total weight of the clear layer) of the INSPIRE 404 polypropylenecopolymer to a twin screw extruder. The INSPIRE 404 polypropylenecopolymer acts as a carrier resin in this stage of the process. Theextruded product is a pelletized additive concentrate.

The clear layer was then fabricated by feeding the remainingapproximately 90% of the INSPIRE 404 polypropylene copolymer to a singlescrew extruder along with the additive concentrate. The additiveconcentrate makes up about 10% of the total weight of the clear layer.

Color Layer

An additive concentrate was made for the color layer, just as describedabove for the clear layer of Example 5.

Additionally, a first color concentrate was made by combining water, theorganic pigments (Perylene Red 179 229-8436 and DPP Red 254 Cromophtal2030) and organic pigment carrier (AC540 Wax). The water is displaced bythe addition of the organic pigment carrier during a flushing process,as described in U.S. patent publication 2005/0282962.

A second color concentrate was made by adding the inorganic pigment andinorganic carrier resin (LLDPE) to a mill.

The color layer was then fabricated by feeding the INSPIRE 404polypropylene copolymer to a single screw extruder along with additiveconcentrate and the first and second color concentrates in the amountsshown in the formula above.

Backing Layer

In a separate process, a Farrell Continuous Mixer was loaded withPro-Fax 7823 polypropylene and the DFDB 1088NT very low densitypolyethylene. Talc and the other additives listed in the formula forExample 5 were added also. The product of the mixer was natural TPO inpellet form.

The color concentrate pellets and the natural TPO pellets were thenadded to a single screw extruder, which produced the backing layer.

Coextrusion Setup

The single screw extruders for the clear, color, and backing layers werepositioned so that each layer would be coextruded in a multilayer stack.

Process for Example 6

Clear Layer

The clear layer was made by the process described above in Example 2,but with the formula for Example 6.

Colored Backing Layer

The colored backing layer was made by the process described above inExample 2, but with the formula for Example 6.

Coextrusion Setup

The single screw extruders for the clear and colored backing layers werepositioned so that each layer would be coextruded in a multilayer stack.

Results

Table 1 summarizes the advantages over competitive technologies in termsof design simplification, design flexibility, process flexibility, &environmental friendliness. Table 2 shows that the multilayer sheets inolefinic Examples 2-6 display the best overall durability performance incomparison to competitive designs. The comparative example of apolyolefin material with block copolymer base and no slip additive isprospective based on known polypropylene examples with no additives.

TABLE 1 Olefinic Examples Iono- Acrylic/ Solvent Painted Painted 2-6 merABS Cast Plastic Metal Paint Yes Yes Yes No No No Free/ Recyclable NoAdhesive Yes No Yes No No No Between Color & Backing Layers Can Be YesYes No No No No Laminated or Directly Formed Can Be Used Yes Yes No YesNo No as a Tape Product Can Coextrude Yes Yes Yes No No No the EntireStructure from Thin to Thick Sheet With No Change in Tooling Colorretention Pass Pass Pass Fail Fail Fail vs. percent elongation (1.0delta E max @ 60%)

TABLE 2 Prospective Comparative Example Acrylic/ Olefin ABS or w/blockAcrylic/ Solvent Olefinic copolymer ASA or Cast Pass/Fail Examples baseand no PC/ASA Fluoro- Painted Painted Test Standard Criteria 2-6 slipadditive Ionomer or PC Acrylic Plastic Metal Imprint Honda #16 NoImprint, Pass Pass Fail Pass Pass Pass Pass Resistance No @ 70° C.Adhesion Oil GM9533P Compare to Pass Pass Fail Pass Pass Pass (8) PassResistance Control (8-10) (4) (10) (10) (8) @ 70° C. Grease GM9533PCompare to Pass Pass Fail Pass Pass Fail (6) Fail Resistance Control(8-10) (4) (10) (10) (6) @ 70° C. Egg GM9533P Compare to Pass Pass FailPass Fail Pass (8) Fail (6) Albumin Control (10) (4) (10) (6-8)Resistance @ 70° C. Methanol GM9509P 1 Pass Pass Pass Pass Pass PassPass Resistance maximum @ RT Scratch & GMW3943 Compare to Pass Fail PassFail Pass Pass Pass Mar Control Resistance Gravelometer GM9508P 7 orgreater 9 Fail 9 Fails <7 <7 <7 5 pints/ (cracks) 90° Impact angle/ −30°C. Gravelometer GM9508P 7 or greater 9 Fail 7 but Fails <7 <7 <7 10pints/ failed (cracks) 30° due to degree delamination impact angle/ −30°C. Low Temp GM 9904P All ductile Pass Pass Pass Fail Fail Fail PassImpact GMP.E/P. failures shatters 148 @ −30° C. Crock Mar CLP 463Compare to Pass Fail Fail Fail Pass Pass Pass PB-54 Control GM9533PScale: 10 = no change, 8 = Slight, 6 = Moderate, 4 = Pronounced, 2 =Severe GM9509P Scale: 0 = no change, 1 = Slight, 3 = Moderate, 5 =Severe GM9508P Scale: 0 = Fail, 1 = Poor−, 2 = Poor, 3 = Poor+, 4 =Fair−, 5 = Fair, 6 = Fair+, 7 = Good−, 8 = Good, 9 = Good+, 10 = nodamage/no chipping GMW3943 Scale: 1 = no scratch, 2, 3, 4, 5 = Worst Thetest standards used above are available from General Motors, Honda, andChrysler. Testing was performed by Ghesquire Plastic Testing, Inc. ofHarper Woods, MI and A. Schulman Invision of Sharon Center, OH.

In summary, the favorable results for the example olefinic multilayerstructures shown in both tables were made without sacrificing the highgloss and DOI requirements that are needed in order to achieve a Class“A” surface.

Examples 1A-8A

Examples 1A-8A illustrate the unexpected results obtained by using amulti-layered virgin/regrind/virgin backing layer instead of a blendedregrind and virgin monolayer backing layer. FIG. 10 shows an ABA backinglayer 90 that corresponds to Examples 1A-4A. FIG. 10 also shows amonolayer backing layer 100 that corresponds to Examples 5A-8A. Bothstructures 90, 100 were 100 mils in thickness in all the Examples 1A-8A.

Example 1A is a control showing a single A layer that is not blendedwith regrind.

In Examples 2A-4A, the A layers are coextruded with the B layer adjacentto them. The A layer is composed of the materials as specified in Table3. Percentages are given in weight percents. Though fillers, colorants,stabilizers and other additives are present, the polymeric base is 100%virgin polymer. The B layer is composed of regrind miscellaneouspolypropylene homo- and copolymers with talc, filler, colorants, andstabilizers. The polymeric base of the B layer is 100% regrind polymer.Examples 1A-4A vary in the thickness of the A layers and the B layers.In Examples 2A-4A the two A layers in each Example are of equalthicknesses, in values of 40 mil, 30 mil, and 20 mil, respectively.

In Examples 5A-7A regrind is blended with the virgin polymer and otheradditives in the amounts disclosed in Table 4. Example 8A is a controlusing 100% regrind. The same type of regrind material was used inExamples 5A-8A as was used in Examples 2A-4A. The structure in Examples5A-8A is a single-layer extruded sheet.

TABLE 3 Example 1A 2A 3A 4A A/B/A Layer Thicknesses Total A Layerthickness (mils) 100 80.0 60.0 40.0 B Layer thickness (mils) 0.00 20.040.0 60.0 A Layer Composition Pro-Fax 7823 PP (%) 64.301 64.301 64.30164.301 DFDB 1088 NT VLDPE (%) 7.920 7.920 7.920 7.920 Premium HTP Ultra5L 25.245 25.245 25.245 25.245 (talc filler) (%) TR016 wax 0.594 0.5940.594 0.594 (process aid & dispersing aid) (%) Chimassorb 119 (UVstabilizer) 0.297 0.297 0.297 0.297 (%) Synpro 12B Calcium Stearate0.049 0.049 0.049 0.049 (process aid & dispersing aid) (%) Evanstab 18DSTDP (Evans 0.198 0.198 0.198 0.198 Chemetics) (antioxidant) IrganoxB225 (CIBA) (antioxidant) 0.396 0.396 0.396 0.396 (%) Polyblak 3123B (A.Schulman) 1.000 1.000 1.000 1.000 (black color concentrate) (%)

TABLE 4 Example 5A 6A 7A 8A Total Mono Layer thickness (mils) 100 100100 100 Mono-Layer Composition Pro-Fax 7823 PP (%) 51.440 38.580 25.7200.000 DFDB 1088 NT VLDPE (%) 6.336 4.752 3.168 0.000 Premium HTP Ultra5L (talc filler) 20.196 15.147 10.098 0.000 (%) TR016 wax (process aid &0.475 0.356 0.238 0.000 dispersing aid) (%) Chimassorb 119 (UVstabilizer) 0.238 0.178 0.119 0.000 (%) Synpro 12B Calcium Stearate0.040 0.030 0.020 0.000 (process aid & dispersing aid) (%) Evanstab 18DSTDP (antioxidant) 0.158 0.119 0.079 0.000 Irganox B225 (antioxidant)(%) 0.317 0.238 0.158 0.000 Polyblak 3123B (black color 1.000 1.0001.000 1.000 concentrate) (%) Regrind (%) 19.800 39.600 59.400 99.000

The A layers of Examples 1A-4A were made by the following process. ThePro-Fax 7823 polypropylene and the DFDB 1088NT very low densitypolyethylene were fed into a Farrell Continuous Mixer. Talc and theother additives listed in Tables 3 were also added. The product of themixer was natural TPO in pellet form. In the next step, pelletized blackcolor concentrate and the natural TPO pellets were added to a singlescrew extruder.

The mono-layer Example 1A was the product of extruding the A layer as amono-layer sheet.

The B layers of Examples 2A-4A were made by feeding pelletized andground up regrind to a single screw extruder.

In Examples 2A-4A, the extruders were positioned so that each layerwould be coextruded in a multilayer stack.

In Examples 5A-7A Pro-Fax 7823 polypropylene and the DFDB 1088NT verylow density polyethylene were fed to a Farrell Continuous Mixer. Talcand the other additives listed in Table 4 were also added. The productof the mixer was a virgin TPO in pellet form. In the next step,pelletized black color concentrate, the virgin TPO pellets, and regrindwere added to a single screw extruder and extruded as a mono-layersheet.

Example 8A was made by the same process as Examples 4A-7A, except novirgin polymer “Pro-Fax 7823 polypropylene” was added.

Results

FIG. 11 compares the virgin backing layer of Example 1 and thevirgin/regrind/virgin ABA structured backing layers of Examples 2A-4A tothe mono-layer structured backing layers of Examples 5A-8A. Inparticular, FIG. 11 shows the impact of varying amounts of regrind onsag resistance for each type of structure. In these Examples, sagresistance was measured in terms of “bag time,” which is the amount oftime required to reach a bag depth of seven inches after heating of thesheet is initiated. The sheet sample size was 40 inches by 20 inches.The sample was heated at 340° F. on a thermoformer. As the data shows,the “bag time” decreases (decreasing sag resistance) as the % regrindincreases in both sets of Examples. However, Examples 2A to 4A showimproved sag resistance versus Examples 5A to 7A. For example,improvements of 3.5% or greater in terms of time to bag, such as 5% andgreater are exhibited by Examples 2A to 4A over Examples 5A to 7A.

In addition, other properties of the ABA structured backing layer showunexpected improvement compared to the blended mono-layer structure.Table 5 summarizes the results of additional testing performed onExamples 1A-8A. The columns are offset so that Examples that aredirectly comparative in terms of regrind percentage are in verticalalignment.

TABLE 5 Example 1A 2A 3A 4A Flex Mod (MPa) 2520 2612 2559 2391 % Elong @Break 327 311 251 199 Tensile @ Yield (MPa) 19 19.3 19.8 21Ductile/Brittle Pt (° C.) −20 −20 −20 −10 Energy to Max Load (J) 29 2931 29 Total Energy (J) 49 49 51 49 Example 5A 6A 7A 8A Flex Mod (MPa)2474 2278 2030 1278 % Elong @ Break 325 251 264 33 Tensile @ Yield (Mpa)19 19 20 19 Ductile/Brittle Pt (° C.) −10 −10 −10 brittle @ 0 Energy toMax Load (J) 30 30 31 3 Total Energy (J) 51 49 51 4

The flexural modulus was tested according ISO 178 at 2 mm/min and a 64mm span. The elongation at break and tensile at yield parameters weretested according to ISO 527 at 50 mm/min. The ductile/brittle point,energy to Max Load, and total energy measurements were tested accordingto GM9904P at 2.2 m/s. For the flexural modulus, percent elongation atbreak, and tensile at yield tests, the samples were cut parallel to thedirection of the extrusion flow.

This written description sets forth the best mode of the invention, anddescribes the invention so as to enable a person skilled in the art tomake and use the invention, by presenting examples. The patentable scopeof the invention is defined by the claims, and may include otherexamples that occur to those skilled in the art.

1. A multilayer structure comprising: a first thermoplastic layer havinga polymeric component consisting essentially of virgin polyolefin; asecond thermoplastic layer including regrind polyolefin; and a thirdthermoplastic layer having a polymeric component consisting essentiallyof virgin polyolefin; the second thermoplastic layer being adjacent tothe first thermoplastic layer and the third thermoplastic layer.
 2. Themultilayer structure of claim 1 wherein the multilayer structureincludes a clear polymer layer.
 3. The multilayer structure of claim 1wherein the polymeric component of the second layer consists essentiallyof regrind.
 4. The multilayer structure of claim 3 wherein the bagstrength of the first, second, and third layer is at least 5% greaterthan a control sample that is identical to the first, second, and thirdlayer in formulation and dimension, but has a mono-layer structure thatincorporates a blend of the regrind and the virgin polymer instead of amulti-layered structure.
 5. The multilayer structure of claim 2 whereinthe multilayer structure further comprises a colored polymeric layeradjacent to the clear layer.
 6. The multilayer structure of claim 1wherein the virgin polyolefin comprises a propylene homopolymer or acopolymer including polypropylene, and further comprises a very lowdensity polyethylene.
 7. A backing layer for a multilayered polymericstructure comprising: a first thermoplastic layer including a polymericcomponent, wherein the polymeric component consists essentially of avirgin polyolefin; a second thermoplastic layer including regrindpolyolefin; a third thermoplastic layer having a polymeric component,wherein the polymeric component consists essentially of a virginpolyolefin; the second thermoplastic layer being adjacent to the firstthermoplastic layer and the third thermoplastic layer, if present. 8.The backing layer of claim 7 wherein the polymeric component of thesecond layer consists essentially of regrind.
 9. The backing layer ofclaim 7 wherein the bag strength of the backing layer is at least 3%higher in terms of the time to bag, than a control sample that isidentical to the backing layer in formulation and dimension, but has amono-layer structure that incorporates a blend of the regrind and thevirgin polymer instead of a multi-layered structure.
 10. The backinglayer of claim 7 wherein the virgin polyolefin comprises a propylenehomopolymer or a copolymer including polypropylene, and furthercomprises a very low density polyethylene.
 11. A method for forming amultilayered polymeric structure, the method comprising coextruding afirst thermoplastic layer having a polymeric component that consistsessentially of a virgin polyolefin, with a second thermoplastic layerincluding regrind polyolefin, and a third thermoplastic layer having apolymeric component that consists essentially of a virgin polyolefin;the second thermoplastic layer being adjacent to the first thermoplasticlayer and the third thermoplastic layer.
 12. The method of claim 11wherein the coextrusion step further comprises coextruding a clearpolymeric layer with the first, second, and third thermoplastic layers.13. The method of claim 11 wherein the coextrusion step furthercomprises coextruding a clear polymeric layer and a colored polymericlayer with the first, second, and third thermoplastic layers.
 14. Themethod of claim 11 further comprising thermoforming the coextrudedmultilayered polymeric structure to make a formed product.
 15. Themethod of claim 11 wherein the polymeric component of the second layerconsists essentially of regrind.
 16. The method of claim 11 wherein thevirgin polyolefin comprises a propylene homopolymer or a copolymerincluding polypropylene, and further comprises a very low densitypolyethylene.
 17. The method claim of 11 wherein the formed product is abacking layer for a vehicle body panel.
 18. The method of claim 11wherein the bag strength of the multilayered polymeric structure aftercoextrusion is at least 3% higher in terms of the time to bag, than acontrol sample that is identical to the backing layer in formulation anddimension but has a mono-layer structure that incorporates a blend ofthe regrind and the virgin polymer instead of a multi-layered structure.